package com.test;

import java.util.HashMap;

public class Main {
    public static void main(String[] args) {
        System.out.println("hello,world!!!");
        HashMap<String,String> map = new HashMap<>();
        map.put("name","张三");
        System.out.println(map.get("name"));
        //System.out.println(map.remove("name"));
        System.out.println(map.replace("name","李四"));
        System.out.println(map);
    }
}
